This invention relates to an apparatus and method for making blocks and, in particular, to an apparatus and method for making blocks from earth or soil materials
Earth or soil materials such as, for example, adobe containing materials have long been used to make blocks in areas where arid conditions generally exist such as, for example, in the Southwest United States. Under these conditions, the blocks can be satisfactorily used to construct walls for homes and other buildings and structures.
The earliest procedure for making adobe blocks comprised placing the adobe mud in uniform sized wood forms and then allowing the sun to bake the mud. This procedure is still followed today and has been enhanced by the addition of stabilizing materials to the mud which enables the adobe blocks to better withstand the elements of wind and rain.
A disadvantage of the above procedure is that it usually requires the manufactured blocks to be transported from the manufacturing site to the construction site. Thus, in the Southwest, for example, blocks are made using this procedure in adobe yards primarily located along the more densely populated Rio Grande River corridor and in the Tucson, Phoenix, Arizona area. As a result, construction with adobe block any distance from this location becomes extremely expensive.
Furthermore, even for locations near the manufacturing site, the cost of using adobe block made by the sun baked method is still more expensive than the use of more modern conventional substitutes such as, for example, cinder block due to the increased labor expenses. As a result, a variety of attempts have been made to develop a less expensive means to construct adobe block than the sun baked method. These attempts have centered around developing machines which can be brought on-site and which can be used for immediate production of blocks through the use of existing on-site material or material transported to the site as unprepared soil. These prior art machines, typically, employ a ram or other type of compression member to compress the adobe material in a mold or compression chamber to the point of fusion.
U.S. Pat. No. 2,388,679 discloses an early machine of the type wherein a mold box carried on a wheeled chassis is used as the compression chamber. In this case, the adobe material is hand filled into the mold box and is compressed by a horizontally moving ram also supported on the chassis. The ram compresses the material to a preselected pressure which is stated to be in a range from 1,000 to 1,200 pounds per square inch. After the compressive forces form the material into a block, the block is removed by hand from the mold.
It is stated in the '679 patent that the resultant blocks produced by the machine are relatively smooth and close to dimension and, as a result, that thin mortar can be used when laying the blocks. This is said to reduce the labor costs and material costs of the construction.
Another more recent adobe block making machine is disclosed in U.S. Pat. No. 3,225,409. This machine is also wheeled for movement to the work site and also employs a horizontally moving ram to compress adobe material in a mold chamber. In this machine, however, the mold chamber is formed, by the sidewalls and bottom walls of an upwardly opened trough, by an end wall removably disposable in the trough opposite the ram which moves along the trough, and by a removable lid which closes the top of the trough. Dirt to be supplied to the mold chamber is situated in a bin supported above the trough. The bin, in turn, is supplied with dirt by a paddle arrangement which functions as an auger.
In operation of the '409 patent machine, the operator raises the lid over the trough and the operator moves dirt by hand from the bin to the trough. The lid is then closed by the operator and the end wall placed in position in the trough to form a compression chamber. The ram is then actuated to compress the dirt and form a block. Subsequent blocks are formed in a like manner until the trough is filled with blocks. At this point, each new block being formed can be compressed against the large flat face of the preceding block and the end wall need not be used.
The blocks formed with the '409 machine have length and width dimensions which correspond to the width and height of the trough and a thickness dimension which corresponds to the horizontal distance between the extended ram and the end wall. This patent thus takes the direction of compressing the block through its thickness and over a surface area corresponding to the largest surface of the block. As a result, the latter surface is in a position facing the ram so as to to enable use of a block as an end wall upon filling of the trough. As stated in the patent, the large flat face of the block is preferably 10 inches by 14 inches and the block has a thickness of 4 inches.
As can be appreciated, the above machines, to a large degree, depend upon the operator to load the machines and to remove formed blocks from the machines. The need to have the operator perform these functions, however, slows down the operating speed of the machines and the number of blocks produced per minute is relatively low.
In an attempt to increase machine output, designers of more recent adobe block making machines have moved in the direction of automating the aforementioned tasks previously carried out by the machine operators. Thus, these new machines have been designed so as to avoid the necessity of having to fill the compression chamber or mold by hand, as is necessary in the above machines. Also, they have been designed to better automate the process of ejecting a completed block from the mold chamber. In order to accomodate these additional features, machine designers have turned to machines which press from above, i.e., whose rams move vertically, and which press through the thickness and, thus, against the largest surface of a block.
In one such machine designed by applicant, the adobe containing dirt is gravity fed from a bin to an auger which carries the dirt to a moving drawer. The latter, in turn, conveys the dirt to a mold chamber which is open from the top and whose height, width an length correspond to the height, width and length of the block. A ram moving vertically along the chamber height then compresses the dirt to a pressure of about 1,200 pounds per square inch. The resultant block is then ejected from the chamber by opening of the chamber bottom wall.
While successfully automating the delivery and ejection processes, the latter type machines suffer from a variety of disadvantages. One significant disadvantage is that they press against the largest surface of a block. As a result, they require large ram assemblies. This, in turn, necessitates the use of heavy steel for the machine construction and large diesel motors for power. Power consumption and cost of materials is thus high making the overall cost of the machine high. Increased block output is therefore realized with these machines, but only at the expense of significantly increasing machine cost.
Another disadvantage of these automated machines is that they produce blocks having thicknesses which vary from block to block. This increases the labor and material costs attendant laying of the blocks, since mortar must now be provided between the blocks to maintain a level wall. This, in turn, makes the use of the machines even more expensive.
It is therefore an object of the present invention to provide an apparatus for making block which does not suffer from the above disadvantages.
It is a further object of the present invention to provide an apparatus for making block which is lighter in weight and which requires less power than previous machines.
It is yet another object of the present invention to provide an apparatus for making block which results in blocks of substantially uniform thickness and with variations only in their lengths, so that little or no adjustment requirements are needed when the blocks are laid.
It is still a further object of the invention to provide an apparatus for making block whose output is increased and whose cost is decreased as compared to previous machines.